STORM-2548 on 1.x-branch broke setting key/value deserializers with the now deprecated setKey/setValue methods

When STORM-2548 was backported, the setKey/setValue methods on KafkaSpoutConfig.Builder were deprecated, and users were directed to use setProp along with the relevant ConsumerConfig constants for setting deserializers instead.

As part of this change, the KafkaConsumerFactoryDefault switched from using the KafkaConsumer(props, keyDes, valDes) constructor to using the KafkaConsumer(props) constructor. Unfortunately I forgot to update the KafkaSpoutConfig.Builder constructor properly, so if the user configures the deserializer via either the Builder constructor parameters or setKey/setValue, the setting is not put in the kafkaProps map and the deserializer is not used.